cynthia mcfadden, bill weir, and tonight, juju chang in new york city, this is "nightline," december 25th, 2012. good evening. i'm juju chang. tonight, a massive christmas day storm is creating blizzard conditions across the nation's midsection. in texas and oklahoma, icy roads cause major pile-ups and deadly traffic mishaps. the storm system also spawned a cluster of tornados throughout the deep south, causing extensionive damage. thousands of residents lost power in mobile, alabama. the facade was torn off a historic church was 24 hours earlier hosted christmas eve services for hundreds of worshippers. but we turn now to the journey of a lifetime, on a quest in search of an elusive creature known as the unicorn of the sea. it's the narwal, both rare and endangered. what we discovered was a landscape vast and beautiful, and sometimes deadly and one

that's changing rapidly. so now an encore presentation of nbc's lindsay davis and producer alex waterfield's journey to the far north, and just getting there was an adventure of its own. >> reporter: it's the middle of the night in the middle of nowhere in one of the most inhospitable places in the world. aside from my guides, i'm all alone. the wind is punishing and the only thing my iphone is good for is taking video. now we're into our third hour . i can't see much through the fog. my three guides are nice, but they're not exactly inspiring confidence right now. what happened? >> it broke. >> reporter: it's broken. we're now down to one snowmobile, we just left our backup behind on the ice, and if

that wasn't bad enough -- are we lost? i think he's joking, but this does not bode well. we're deep inside the arctic circle on baffin island. it's bigger than california, but with only 11,000 inhabitants, it's not the kind of place you can stop to ask for directions. but this is the price of admission for a shot at seeing one of the most elusive creatures on the planet, the narwal, the so called unicorn of the ocean, with that single tusk that can be up to ten feet long. it's the stuff of fantasy, and i for one need to see it to believe it. and sooner rather than later. the narwal is said to be the most vulnerable species in the arctic to climate change, and here the stark reminders of global warming are all around us, like these big cracks in the ice, cracks that shouldn't be this wide this early in the summer. my mom would not be happy about this.

the arctic sea ice is literally disappearing beneath our feet. on track to be faster this year than any other on record. the effects of the rising temperatures up here are dramatic. just a few hundred miles away from us, these tourists had a narrow escape when an ice wave caused by a fallen glacier almost capsized their boat. despite all the obstacles and dangers this far north, we press on, and suddenly i notice some orange domes on the horizon. it's our campsite. we made it. welcome to the edge of the world, right? >> right. so this is our arctic base camp. >> reporter: i'm greeted by tom lenart. the only tour operator that offers land-based trips this far north. lesson number one for new arrivals, know what's beneath your feet. >> we're sitting on about four feet of sea ice with about a thousand feet of water below us.

it appears like it's firm, but it is actually going up and down with the tides as well. >> how do you know that it's safe? i mean i can -- >> you can jump. >> reporter: and i'm not going to end up in the thousand feet of water? >> no, you won't. >> reporter: the dark hole there, that's the ocean? that's all that's separating us. >> that's it. don't think about it. >> reporter: finally, we head to the edge where the sea ice meets the open water. one of the richest and most diverse ecosystems on the planet. >> i never get sick of it. planet with six billion people and we're one of 20 people watching this. i feel privileged every time we come here. >> reporter: as the ice continues to disappear, so too will this fragile ecosystem, taking the narwal with it. >> it's cold. got the rain coming down. it's sleet. but we're going to see some narwals and that makes everything okay. >> reporter: eric coombs is a

budding wildlife photographer and he's on a mission. >> if we can get those nalwals shooting up their big long ivory tusks, that's the pinnacle moment of seeing a narwal. >> reporter: but before you see them, you can often hear them, which is why these headphones attached to a nifty underwater microphone come in handy. this sound right here might as well be trumpeters announcing their presence. >> in the open water. >> reporter: and then it happens. the rare moment we've come all this way for. >> in the ice over there. >> reporter: when we come back, a close encounter with these mythical creatures and a close brush with a thousand feet of open sea. as an unexpected crack in the ice threatens to leave us stranded. [ male announcer ] this is the age of knowing what you're made of.

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"nightline" continues from new york city with juju chang. >> and now, we rejoin lindsay and the team for a very close encount we are the mysterious narwal. and then, the mortal threat they face on the arctic ice. once again, lindsay davis. >> reporter: through the fog, which seems to make this moment all the more mystical -- >> he's just behind that pack of ice over there. >> reporter: they spot it. an arched back off in the distance. quite a sight for sore eyes. >> i can't believe it. we've actually seen our narwal. so they exist. they're not imaginary. >> reporter: there's actually one right there. and then another. this one much closer to the edge. before we know it, narwals are everywhere.

>> there's so many. there's like six or seven of them. >> reporter: but we were hoping for a slightly closer encounter. so we venture out with our fearless leader into narwal territory. >> so, lindsay, you're kayaking in the arctic. >> reporter: i am kayaking in the arctic. this area is t >> this area is the only place in the world to see the narwal. did you hear that? >> reporter: absolutely, we hear something very close take a a massive gasp of air. >> you see that right there? >> reporter: the fog clears just long enough for us to realize we're surrounded. they're all around us now. and for just a second we spot it. don't blink or you'll miss it. that ivory tusk. that's very cool. >> that was awesome. what got me hooked on the arctic was they've chosen to come to you. >> reporter: and you're not afraid? >> no. they're not going to hurt you. they're just curious.

they're just wondering what are you doing here? this is my backyard. >> reporter: but just as quickly as the narwals appear, they're gone. a reminder of just how vulnerable these creatures are to climate change. but rising temperatures aren't just affecting the narwal. there are four million people living here in the arctic. as our guide showed me, this is not a winter safari destination. it's his home. the sea ice is his highway, his livelihood. it's how he feeds his family. >> i love hunting. >> reporter: that's one of your favorite things to do? >> yeah. >> reporter: hunting for seals. >> yeah. >> reporter: we see for ourselves that hunting seal isn't easy. and with temperatures rising, it's getting harder. the ice is too slushy for most of the gear for him to use a traditional dog team. the iron dog he now uses isn't exactly stealthy. the seals can hear him coming from miles away, and then escape

down their holes into the ocean below. >> oh! >> reporter: oh, i think he's very cute. that is when they can escape. we're on our way back from a day of narwal searching when we saw a pup seal. a word of warning, what you're about to see is graphic. is it sad at all? it seemed like such a cute -- it was a little baby that lost its life. >> it's not a baby, it's just an animal. it's given to us. the creator gave us this meat so we can survive on it. >> reporter: how do you explain it to westerners who say it's cruelty to animals. >> this is not cruelty. this is how we survived for thousands of years. >> reporter: a way of life that's slowly disappearing. weather and ice patterns are becoming more unpredictable, as

we are about to find out in a frightening way firsthand. back at camp just a few hours later, a crisis. suddenly we find ourselves at the mercy of the rapidly melting ice. >> there's a big crack that's opening up between us. it's meltsed faster than it should have. the elders have said that we should pack up and go. >> reporter: a crack in the ice that's growing with every passing minute. if it gets any wider, it might become impassable, leaving our entire group stranded on the sea ice. tom, our team leader, is playing it cool. >> no, i'm not stressed. when i have these guys around, i've got complete confidence. we'll get it done. not worried yet. not yet. >> reporter: but wildlife photographer eric puts the situation in starker terms. >> we're going to have to leave immediately and hopefully we'll be able to make it back before we float off into the ocean.

>> reporter: it's all hands on deck to break down the situation as quickly as possible. a bit of trepidation thus far about the crack. we'll see. the race against mother nature is on, and what i see along the way is ominous. >> there's so much more water now compared to when i first came out here. it was just massive expanses of ice before. and now it's like little islands of ice. we press on. not even a smoking snowmobile is good enough reason to stop. until we arrive at the so called crack, which looks a lot more like a lake, and that blue water, open blue ocean, a thousand feet deep. >> this has all happened in less than six days. basically it will be five times the size that it was a week ago. >> reporter: suddenly, the sound of roaring engines.

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and now the race against the melting ice in the arctic continues, and our intrepided a

adventurers prepare to make their dash for safety. once again, lindsay davis. >> reporter: the snowmobiles make it across the crack. is it intended to go over water like that? >> it's not intended to, but people do it. with enough speed. >> reporter: we see for ourselves what can happen if you don't have enough speed. a very close call. but what about the rest of us? and the sleds. the guides examine a large chunk of ice floating in the middle of the crack to see if it will work as a bridge. team leader tom is still playing it cool, but even he admits it's an audacious plan. >> i've done big cracks. not as big as this one. but i have full in these guys. this is the arctic, and this is their backyard and they know what they're doing. >> reporter: so not a doubt in your mind everybody's going to make it across? >> i'll get you home, don't worry. >> reporter: i appreciate that. the laughter quickly dissipates. this is the moment of truth.

as the natives test the limits of these sleds and their ability to make it across. the first sled does not farewell. it careens across the crack like a runaway train. no one is acting very concerned. i'm thinking that this is pretty dangerous. just as i start to think about the worst case scenario, it's my turn. you think we're going to be fine? >> yeah. should be fine. >> reporter: should be fine. should be? okay, all right. if you say so. all right. we made it. thank you! the entire team is briefly dipped in the arctic as it makes its way across with varying degrees of success. >> you okay?

>> reporter: but success nonetheless. >> that's everyone. we're across the crack. piece of cake. >> reporter: tragedy averted, at least in the short term. but the long-term outlook is rather bleak. take a look at how much ice there was in the arctic during the summer just few decades back. now fast forward to what's left today. scientists say at the current rates, summer sea ice in the arctic will almost certainly be gone in the next ten to 20 years. we saw firsthand the melting of the ice is cause for real concern. let's not talk about it because i might chicken out. in fact, there was only one occasion where we saw the benefit of a crack in the ice. >> you should do the rocky. >> reporter: and that was to fulfill a long-standing arctic tradition that i just had to try before going home. i'm glad you're so excited about this. taking the polar bear plunge. this is the stupidest thing i've

ever done. and trust me, membership is not for the feint of heart. >> whoo! >> reporter: it was pretty fun. i want to do it again. that was great. as we make our way back to solid land, the fog that's been dogging us all week starts to lift, unveiling a bright blue arctic sky. and though i was too exhausted to enjoy it, i'm told the view was breathtaking. for "nightline," i'm lindsay davis. >> our collective hats off and our thanks to lindsay davis and alex waterfield. tomorrow night, a special edition of "nightline" -- christmas at the white house with barbara walters. thank you for watching abc news. we hope you check in for "good morning america." they will have all the latest on the severe weather throughout

the country that's now headed east. we're always online, as you know, at abcnews.com. jimmy kimmel is next. we'll see you here tomorrow. good night. >> dicky: up next on "jimmy kimmel live" -- >> i'm hoping that obama announces this will be the black half of his presidency. >> dicky: john goodman. >> jimmy: have you ever actually emptied a mini bar on your own? >> you bet. >> dicky: hayden panettiere. >> jimmy: i would not want to be paul ryan's shake weight